1. Field of Invention
The present invention relates to an auxiliary fixture, and more particularly to an auxiliary fixture for a tire pressure monitoring device that may assemble the tire pressure monitoring device in a tire rim accurately, may be adjustable in use, and may disassemble the tire pressure monitoring device from the tire rim quickly.
2. Description of the Related Art
Conventional tire pressure monitoring systems (TPMS) can be classified into a direct-type TPMS and an indirect-type TPMS. The direct-type TPMS has a sensor mounted in a tire to directly detect the air pressure of the tire and to enable the driver to know the actual air pressure of the tire to keep the tire in a stable condition. The indirect-type TPMS has a wheel speed sensor mounted in a braking system of a vehicle to detect the air pressure of the tire by comparing the speed difference of the wheels of the vehicle. With the advances in wireless communication technology, the direct-type TPMS has gradually become the trend of a variety of vehicles to assemble.
With reference to FIG. 21, the conventional direct-type TPMS has a tire pressure monitoring device 50 with a valve stem 51 and a sensor 52 connected to the valve stem 51. The conventional TPMS is assembled in a tire rim 60 by a conventional auxiliary fixture 70, and is connected to an electronic system of a vehicle by wireless communication to provide the air pressure of the tire to the user. In order to assemble the sensor 52 of the conventional direct-type TPMS in the tire rim 60, the conventional auxiliary fixture 70 has a handle 71 and a connecting sleeve 72 pivotally connected to the handle 71. In assembly, a free end of the valve stem 51 of the conventional direct-type TPMS extends through a valve hole 61 of the tire rim 60, and a cap deposited on the free end of the valve stem 51 is released. The connecting sleeve 72 is connected to the free end of the valve stem 51 by screw, and the handle 71 abuts against an outer flange of the tire rim 60 and a downward force is applied on the handle 71. Then, the connecting sleeve 72 is moved upwardly relative to the tire rim 60, and this enables the valve stem 51 that is connected to the connecting sleeve 72 to move up relative to the tire rim 60. Consequently, the valve stem 51 engages in the valve hole 61 of the tire rim 60, and the sensor 52 is deposited in the tire rim 60.
Although the conventional auxiliary fixture 70 may provide an assembling effect to the conventional direct-type TPMS, the conventional direct-type TPMS is securely deposited in the tire rim 60 by pulling the valve stem 51, and this may affect the condition of an axial center of the valve stem 51 aligning with a center of the valve hole 61 when the direction of the downward force or the operator is different. When the axial center of the valve stem 51 is not aligned with the center of the valve hole 61, this means the valve stem 51 is not connected to the valve hole 61 tightly, and the gas in the tire may leak out of the tire via a gap between the valve stem 51 and the valve hole 61. Furthermore, when the valve stem 51 is not correctly deposited in the valve hole 61 and needs to be reassembled, a sheath that is made of rubber material is mounted around an external surface of the valve stem 51, and the sheath may be damaged or broken by a periphery of the tire rim 60 around the valve hole 61 during disassembling of the valve stem 51 from the valve hole 61. Then, the valve stem 51 cannot be used again and this is inconvenient in assembly and may increase the cost of the use. Therefore, the conventional auxiliary fixture 70 still has many problems and inconvenience in use.
With reference to FIG. 22, in view of the aforementioned problems of the conventional auxiliary fixture 70, another conventional auxiliary fixture 80 has been developed and has a handle 81, a positioning base 82, and a holding lever 83. The handle 81 has two abutting wheels 811 deposited at a front end of the handle 81 at a spaced interval. The positioning base 82 is pivotally connected to the front end of the handle 81 and has a positioning recess formed in a front side of the positioning base 82. The holding lever 83 is pivotally connected to the handle 81, selectively abuts the handle, and has an engaging segment 831 deposited on a top end of the holding lever 83.
When the conventional auxiliary fixture 80 is used to assemble the conventional direct-type TPMS, the sensor 52 of the conventional direct-type TPMS is mounted in the positioning recess of the positioning base 82, and the valve stem 51 extends out of the positioning base 82 and is inserted into the valve hole 61. Additionally, the abutting wheels 811 abut against an inner surface of the tire rim 60, and the engaging segment 831 of the holding lever 83 engages an outer flange of the tire rim 60. When a user presses the handle 81 downwardly, the positioning base 82 is pushed to move toward the valve hole 61 by using a connecting position between the handle 81 and the holding lever 83 as fulcrum, and the valve stem 81 is moved with the sensor 52. Then, the valve stem 51 is pushed to deposit in the valve hole 61. The valve stem 51 is connected to the tire rim 60 by the conventional auxiliary fixture 80 pushing the sensor 52, and this may avoid the influence of different directions of the downward force or different operators by pulling the valve stem 51 via the conventional auxiliary fixture 70.
Although the conventional auxiliary fixture 80 may solve the problems of the conventional auxiliary fixture 70, the sensor 52 of the conventional direct-type TPMS may have different sizes or shapes, and the structure of the positioning base 82 of the conventional auxiliary fixture 80 is fixed and cannot be adjusted. Therefore, when the user needs to assemble the sensors 52 of different sizes on the tire rim 60, the positioning base 82 needs to detach from the handle 81, and a new positioning base 82 of a different size corresponding to the sensor 52 is connected to the handle 81. Then, the sensor 52 can be deposited in the new positioning base 82 to assemble the conventional direct-type TPMS on the tire rim 60, and this may increase the assembling time and the cost of purchasing multiple positioning bases 82 of different sizes. Furthermore, another auxiliary fixture for the conventional direct-type TPMS is also disclosed in US 20160303929 A1, and still has the above-mentioned problems. Consequently, the conventional auxiliary fixtures 70, 80 for tire pressure monitoring device need to be improved.
The auxiliary fixture for a tire pressure monitoring device in accordance with the present invention mitigates or obviates the aforementioned problems.